Referring now to FIG. 1 a typical computer system 10 is shown. In such a computer system 10, because of the physical limitation of the magnetic media and optical media, the access speed of the disk drive 12 is between 0.004 second to 0.1 second. This time frame represents a much slower rate than that of a Central Processing Unit 11 (“CPU”) and the computer system's Random Access Memory 13 (“RAM”), which operates at access times of in several nanoseconds (i.e., 1/1,000,000,000 of a second). The disk drive 12 is therefore the bottleneck of the computer system 10, as it operates much slower than the CPU 11 and RAM 13. Sophisticated operating systems and applications require more and more disk storage. It takes minutes to load an operating system and the applications.
There are some technologies such as advanced disk caching which address some of these issues, but suffer from certain drawbacks. For example. and without limitation, only accessing continuous large blocks of disk data can take advantage of disk caching. Caching or caches consists of a very small amount of high speed SRAM. The content turn-over is very high (almost 100%). It is therefore not intended to store data permanently. Caching does not reduce initial seek time either since any additional data request will be forward to disk drive, whose speed is limited by mechanical rotation of the disk. Another known software technique such as RAMDisk, which uses software to emulate a disk drive with main RAM, improves the speed of accessing temporary data. However when a computer is powered down, the content of the RAMDisk is distorted. RAMDisk also has a very limited size as it is limited by the amount of main memory.
A RAM Storage device can improve the storage performance significantly. But it is very limited in storage capacity with higher cost and less reliability in the event of battery failure. It requires a special device drive to communicate with the Operating System. Once the RAM storage device is installed in a computer system. It is impossible to remove it or upgrading the computer hardware without losing the data. It cannot be retrofitted into an existing computer system, a new Operating System installation is required.
Although a disk drive contains gigabytes of data, only a small portion of the data is recently used, such as swap file, temporary file, operating system files, e-mail system, office program, internet browser, etc.